Abstract: This paper presents an adaptive data fusion method which uses a fuzzy logic controller to online adjust the Kalman filter,and focuses on its application to the integrated GPS/INS navigation.The fuzzy logic controller can continually and optimally adjust the Kalman filter according to PDOP(position dilution of precision) and statistic information of the Kalman filtering innovation,and hence enhances the positioning accuracy of the integrated navigation system.Simulation results indicate that this novel adaptive Kalman filter gives better accuracy than the standard one does.